Curium solution chemistry

An examination of the chemistry of americium indicates that it is intermediate between that of plutonium and that of curium. The chemistry of curium bears a strong resemblance to that of the lanthanides in solution curium exists in the + 3 oxi dation state, although the tetravalent state has been observed as Cm F4 in a solid matrix. 

The only complexes known (Table 90) are those of -ketoenolates with (n-C8Hi7)3PO and (Bu"0)3PO, prepared by solvent extraction from aqueous solutions of the actinides(III) with a mixture of the /S-ketoenol and the P-oxide. There is also solution chemistry evidence for the formation " of Am[CF3COCHCO(2-C4H3S)]3-2(Bu"0)3PO. Am[CF3COCHCOCF3)3-2(Bu"0)3P0 is volatile at 175 and a gas chromatography study of this complex and the curium analogue has been reported. ... 

The aqueous-solution chemistry of curium is almost exclusively that of Cm(iii). Little non-aqueous-solution chemistry has been reported with curium other than that related to solvent extraction [149], Dilute Cm(iii) solutions are normally colorless, but Cm(iii) in concentrated HCl appears greenish. With solutions with concentrations of about 1 gl will boil unless cooled. 

The solution photochemistry of the actinides begins with uranium none has been reported for actinium, thorium, and protactinium. Spectra have been obtained for most of the actinide ions through curium in solution (5). Most studies in actinide photochemistry have been done on uranyl compounds, largely to elucidate the nature of the excited electronic states of the uranyl ion and the details of the mechanisms of its photochemical reactions (5a). Some studies have also been done on the photochemistry of neptunium (6) and plutonium (7). Although not all of these studies are directed specifically toward separations, the chemistry they describe may be applicable. 

Nobelium is a member of the actinide series of elements. The ground state electron configuration is assumed to be (Rn)5fl47s2, by analogy with the equivalent lanthanide element ytterbium ([Kr]4fl46s2) there has never been enough nobelium made to experimentally verify the electronic configuration. Unlike the other actinide elements and the lanthanide elements, nobelium is most stable in solution as the dipositive cation No ". Consequently its chemistry resembles that of the much less chemically stable dipositive lanthanide cations or the common chemistry of the alkaline earth elements. When oxidized to No, nobelium follows the well-estabhshed chemistry of the stable, tripositive rare earth elements and of the other tripositive actinide elements (e.g., americium and curium), see also Actinium Berkelium Einsteinium Fermium Lawrencium Mendele-vium Neptunium Plutonium Protactinium Ruthereordium Thorium Uranium. 

T. Yang and B. E. Bursten, Speciation of the curium(III) ion in aqueous solution a combined study by quantum chemistry and molecular dynamics simulation, Inorg. Chem., 45,5291-5301 (2006). 

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